Core-Shell Silicon Anode Material for Crack-Tolerant Li-Ion Cycling

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Solution Overview

Problem

Silicon-based anode active materials in lithium secondary batteries experience significant volume expansion during charging and discharging, leading to cracks, rapid electrolyte consumption, and reduced lifespan due to side reactions.

Innovation Solution

An anode active material is designed with a core containing a solid electrolyte encapsulated by a silicon-based shell, which protects the electrolyte from initial exposure and allows it to replenish as cracks form, maintaining ionic conductivity and electrolyte supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If silicon-based active material is used as anode, then energy density is improved, but volume expansion causes cracks and rapid electrolyte consumption leading to reduced lifespan

Engineering Contradiction:

Improveenergy densityVSAvoidlifespan

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent embeds a solid electrolyte core within a silicon-based active material shell, creating a nested core-shell structure. The solid electrolyte core is completely enclosed by the silicon-based material, allowing the less stable component to be protected while the stable component provides structural integrity. This nesting resolves the contradiction by containing the volume expansion effects within the shell while maintaining energy density benefits.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The solid electrolyte core acts as a pre-positioned cushioning element that compensates for future electrolyte consumption. When cracks form in the silicon-based shell during cycling, the solid electrolyte core gradually releases electrolyte to replenish what is consumed, thereby cushioning against the harmful effects of electrolyte depletion and extending battery lifespan.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Quantity of substance

If silicon-based active material is used, then capacity is improved, but cracks form due to volume expansion causing rapid electrolyte consumption

Engineering Contradiction:

ImprovecapacityVSAvoidelectrolyte consumption

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The solid electrolyte core is pre-loaded with excess electrolyte material before the battery is assembled. This preliminary action ensures that when cracks form and electrolyte is consumed during cycling, there is a reserved supply within the core to replenish the loss, thereby reducing net electrolyte consumption and extending battery life while maintaining high capacity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The solid electrolyte core continuously releases electrolyte to compensate for consumption during battery cycling. This recovering mechanism ensures that electrolyte lost through cracks and side reactions is replenished from the core, effectively reducing net electrolyte loss while maintaining the high capacity benefits of silicon-based material.

Inventive Principle:

Principle #34Discarding and recovering

3Strength

If shell portion completely surrounds core portion, then structural integrity is improved, but cracks in shell expose core to accelerate degradation

Engineering Contradiction:

Improvestructural integrityVSAvoiddegradation resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent converts the harmful effect of shell cracking into a beneficial mechanism. When cracks form in the silicon-based shell, they enable the solid electrolyte core to release electrolyte that replenishes consumed electrolyte in the bulk. Thus, the crack, which would normally accelerate degradation, actually triggers a self-healing mechanism that extends battery lifespan.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The solid electrolyte core provides self-service by automatically releasing electrolyte when cracks form in the shell. This self-regulating mechanism detects the presence of cracks and responds by replenishing electrolyte without external intervention, thereby converting a structural failure mode into a self-healing feature that improves reliability.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design extends the battery's lifespan by continuously replenishing electrolyte through the solid electrolyte, reducing internal resistance and maintaining power properties over repeated cycles.

Implementation Method 1

an ionic conductivity of the solid electrolyte may be 1×10−4 S/cm or more

Methodology Applied

Scientific EffectIonic conductivity: Conduction (electrical)

Data Source

PatentUS12609300B2Anode active material and lithium secondary battery including the same

Publication Date: 2026.04.21 SK ON CO LTD

AI summary

An anode active material for a lithium secondary battery includes a core portion including a solid electrolyte, and a shell portion encapsulating the core portion and including a silicon-based active material. A lithium secondary includes a case and an electrode assembly accommodated in the case. The electrode assembly includes an anode including the anode active material and a cathode facing the anode.